Ministry of Foreign Affairs Netherlands, Communication Division (DVL/VB) ,
Buku Teks
Standley, Gerald B., author
Houghton Mifflin, 1971
Buku Teks
Mueller, Robert A., author
John Wiley & Sons, 1988
Buku Teks
Barnard, Alan, author
Cambridge University Press, 2012
Buku Teks
Machi, Antonio, author
Springer-Verlag , 2012
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